2023-08-04 10:11:00

by Tony Lindgren

Subject: [PATCH] serial: core: Fix kmemleak issue for serial core device remove

Kmemleak reports issues for serial8250 ports after the hardware specific
driver takes over on boot as noted by Tomi.

The kerneldoc for device_initialize() says we must call device_put()
after calling device_initialize(). We are calling device_put() on the
error path, but are missing it from the device remove path. This causes
release() to never get called for the devices on remove.

Let's add the missing put_device() calls for both serial ctrl and
port devices.

Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Reported-by: Tomi Valkeinen <[email protected]>
Signed-off-by: Tony Lindgren <[email protected]>
---
drivers/tty/serial/serial_base_bus.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
--- a/drivers/tty/serial/serial_base_bus.c
+++ b/drivers/tty/serial/serial_base_bus.c
@@ -99,6 +99,7 @@ void serial_base_ctrl_device_remove(struct serial_ctrl_device *ctrl_dev)
return;

device_del(&ctrl_dev->dev);
+ put_device(&ctrl_dev->dev);
}

struct serial_ctrl_device *serial_base_ctrl_add(struct uart_port *port,
@@ -174,6 +175,7 @@ void serial_base_port_device_remove(struct serial_port_device *port_dev)
return;

device_del(&port_dev->dev);
+ put_device(&port_dev->dev);
}

static int serial_base_init(void)
--
2.41.0

2023-08-04 11:26:14

by Tomi Valkeinen

Subject: Re: [PATCH] serial: core: Fix kmemleak issue for serial core device remove

On 04/08/2023 12:09, Tony Lindgren wrote:
> Kmemleak reports issues for serial8250 ports after the hardware specific
> driver takes over on boot as noted by Tomi.
>
> The kerneldoc for device_initialize() says we must call device_put()
> after calling device_initialize(). We are calling device_put() on the
> error path, but are missing it from the device remove path. This causes
> release() to never get called for the devices on remove.
>
> Let's add the missing put_device() calls for both serial ctrl and
> port devices.
>
> Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
> Reported-by: Tomi Valkeinen <[email protected]>
> Signed-off-by: Tony Lindgren <[email protected]>
> ---
> drivers/tty/serial/serial_base_bus.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
> --- a/drivers/tty/serial/serial_base_bus.c
> +++ b/drivers/tty/serial/serial_base_bus.c
> @@ -99,6 +99,7 @@ void serial_base_ctrl_device_remove(struct serial_ctrl_device *ctrl_dev)
> return;
>
> device_del(&ctrl_dev->dev);
> + put_device(&ctrl_dev->dev);
> }
>
> struct serial_ctrl_device *serial_base_ctrl_add(struct uart_port *port,
> @@ -174,6 +175,7 @@ void serial_base_port_device_remove(struct serial_port_device *port_dev)
> return;
>
> device_del(&port_dev->dev);
> + put_device(&port_dev->dev);
> }
>
> static int serial_base_init(void)

Tested-by: Tomi Valkeinen <[email protected]>

Tomi